Reduced-pressure dressings employing tissue-fixation elements

ABSTRACT

A reduced-pressure system for treating a tissue site on a patient includes a distribution manifold that adheres to a tissue site to allow retention without external support. The distribution manifold includes a porous member and a tissue-fixation element. The tissue-fixation element maintains the porous member substantially adjacent to the tissue site while a sealing member is applied. In one instance, the tissue-fixation element is a soluble adhesive that partially covers either the tissue-facing side of the porous member or a tissue-facing side of a fluid-permeable substrate layer that is on the tissue-facing side of the porous member. Other systems, distributions manifolds, and methods are presented.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/853,407, filed Sep. 14, 2015, which is a divisional of U.S. patentapplication Ser. No. 13/532,074, filed Jun. 25, 2012, now U.S. Pat. No.9,168,179, which claims the benefit, under 35 USC § 119(e), of thefiling of U.S. Provisional Patent Application No. 61/500,915, entitled“Reduced-Pressure Dressings Employing Tissue-Fixation Elements,” filedJun. 24, 2011, all of which are incorporated herein by reference for allpurposes.

BACKGROUND

The present disclosure relates generally to medical treatment systemsand, more particularly, but not by way of limitation, toreduced-pressure dressings employing a tissue-fixation element.

Clinical studies and practice have shown that providing a reducedpressure in proximity to a tissue site augments and accelerates thegrowth of new tissue at the tissue site. The applications of thisphenomenon are numerous, but application of reduced pressure has beenparticularly successful in treating wounds. This treatment (frequentlyreferred to in the medical community as “negative pressure woundtherapy,” “reduced pressure therapy,” or “vacuum therapy”) provides anumber of benefits, which may include faster healing and increasedformulation of granulation tissue. Typically, reduced pressure isapplied to tissue through a porous pad or other manifold device. Theporous pad distributes reduced pressure to the tissue and channelsfluids that are drawn from the tissue. Reduced pressure may also beapplied for other treatments, such as removing fluids.

SUMMARY

According to an illustrative embodiment, a reduced-pressure system fortreating a tissue site includes a distribution manifold, a sealingmember for disposing over the distribution manifold to create a sealedspace containing the distribution manifold, a reduced-pressure sourcefluidly coupled to the sealed space for providing reduced pressure tothe sealed space, and a liquid receptor fluidly coupled to distributionmanifold for receiving fluids from the patient under the influence ofreduced pressure. The distribution manifold includes a porous memberhaving a plurality of flow channels for distributing reduced pressureand receiving fluids. The porous member has a first side and a second,tissue-facing side. The distribution manifold further includes afluid-permeable substrate member having a first side and a second,tissue-facing side. The second, tissue-facing side of the porous memberis disposed proximate to the first side of the fluid-permeable substratemember. The second, tissue-facing side of the fluid-permeable substratemember has a surface area A_(s). The distribution manifold also includesa tissue-fixation element having a first side and a second,tissue-facing side, and wherein the first side of the tissue-fixationelement is coupled to the second, tissue-facing side of thefluid-permeable substrate member. The second, tissue-facing side of thetissue-fixation element has a surface area A_(t). The surface areas,A_(t) and A_(s), are related according to the following expression: 0.05A_(s)<A_(t)<0.6 A_(s).

According to another illustrative embodiment, a method for treating atissue site on a patient with reduced pressure includes the steps oftacking a distribution manifold to the tissue site using atissue-fixation element on the distribution manifold so that thedistribution manifold remains substantially adjacent to the tissue site,covering the distribution manifold with a sealing member to form asealed space containing the distribution manifold, and providing reducedpressure to the sealed space. The distribution manifold includes aporous member for distributing reduced pressure and receiving fluid. Theporous member has a surface area A_(p) facing the tissue site. Thedistribution manifold also includes a tissue-fixation element coupled tothe porous member. The tissue-fixation element has a surface area A_(t)facing the tissue site, and wherein 0.05 A_(p)<A_(t)<0.6 A_(p).

According to another illustrative embodiment, a method of treating atissue site on a patient with reduced pressure includes the steps ofproviding a tack unit, providing a distribution manifold comprising aporous member, disposing the tack unit against the tissue site, anddisposing the distribution manifold against the tack unit such that thedistribution manifold remains adjacent to the tissue site withoutexterior support other than the tack unit and the tissue site. Themethod further includes covering the distribution manifold with asealing member to create a sealed space containing the distributionmanifold, and providing reduced pressure to the sealed space.

According to another illustrative embodiment, a distribution manifoldfor use in a reduced pressure system for providing reduced pressure to atissue site on a patient includes a porous member having a plurality offlow channels for distributing reduced pressure and receiving fluids.The porous member has a first side and a second, tissue-facing side. Thedistribution manifold further includes a fluid-permeable substratemember having a first side and a second, tissue-facing side. The second,tissue-facing side of the porous member is proximate to the first sideof the fluid-permeable substrate member. The second, tissue-facing sideof the fluid-permeable substrate member has a surface area A. Thedistribution manifold also includes a tissue-fixation element having afirst side and a second, tissue-facing side. The first side of thetissue-fixation element is coupled to the second, tissue-facing side ofthe fluid-permeable substrate member. The second, tissue-facing side ofthe tissue-fixation element has a surface area A_(t), and wherein 0.05A_(s)<A_(t)<0.6 A_(s).

According to another illustrative embodiment, a method of manufacturinga distribution manifold for use in a reduced-pressure system forproviding reduced pressure to a tissue site on a patient includes thesteps of providing a porous member having a plurality of flow channelsfor distributing reduced pressure and receiving fluids. The porousmember has a first side and a second, tissue-facing side. The methodfurther includes providing a fluid-permeable substrate member having afirst side and a second, tissue-facing side. The second, tissue-facingside of the fluid-permeable substrate member has a surface area A_(s).The method further includes coupling the second, tissue-facing side ofthe porous member to the first side of the fluid-permeable substratemember and providing a tissue-fixation element having a first side and asecond, tissue-facing side. The second, tissue-facing side of thetissue-fixation element has a surface area A_(t). A_(s) and A_(t) havethe following relationship: 0.05 A_(s)<A_(t)<0.6 A_(s). The methodfurther includes coupling the first side of the tissue-fixation elementto the second, tissue-facing side of the fluid-permeable substratemember.

According to another illustrative embodiment, a method of treating atissue site on a patient with reduced pressure includes the steps ofpositioning the patient in a prevailing position, which is a positionthat the patient will remain for a majority of time during treatment;and using a tissue-fixation element to tack a porous member to thetissue site while the patient remains in the prevailing position. In theprevailing position, the tissue site is substantially parallel to agravitational field. The method further includes covering the porousmember with a sealing member to form a sealed space and providingreduced pressure to the sealed space.

Other features and advantages of the illustrative embodiments willbecome apparent with reference to the drawings and detailed descriptionthat follow.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram with a portion shown in cross section ofan illustrative embodiment of a reduced-pressure system for treating atissue site;

FIG. 2 is a schematic cross section of an illustrative embodiment of adistribution manifold;

FIG. 3 is a schematic bottom (tissue-facing side) plan view of anillustrative embodiment of a porous member and a tissue-fixationelement;

FIG. 4 is a schematic bottom plan view of an illustrative embodiment ofa porous member and a tissue-fixation element;

FIG. 5 is a schematic bottom plan view of an illustrative embodiment ofa porous member and a tissue-fixation element;

FIG. 6 is a schematic bottom plan view of an illustrative embodiment ofa porous member and a tissue-fixation element;

FIG. 7 is a schematic bottom plan view of an illustrative embodiment ofa porous member and a tissue-fixation element;

FIG. 8 is a schematic cross section of a portion of an illustrativeembodiment of a reduced-pressure system for treating a tissue site;

FIG. 9 is a schematic top view of a distribution manifold on a patient;

FIG. 10 is a schematic cross section of a portion of an illustrativeembodiment of a reduced-pressure system for treating a tissue site;

FIG. 11 is a schematic, perspective view of an illustrative embodimentof a porous member having notches; and

FIG. 12 is a schematic, perspective view of an illustrative embodimentof a porous member having notches.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

In the following detailed description of the illustrative, non-limitingembodiments, reference is made to the accompanying drawings that form apart hereof. These embodiments are described in sufficient detail toenable those skilled in the art to practice the invention, and it isunderstood that other embodiments may be utilized and that logicalstructural, mechanical, electrical, and chemical changes may be madewithout departing from the spirit or scope of the invention. To avoiddetail not necessary to enable those skilled in the art to practice theembodiments described herein, the description may omit certaininformation known to those skilled in the art. The following detaileddescription is not to be taken in a limiting sense, and the scope of theillustrative embodiments are defined only by the appended claims.

Referring now primarily to FIGS. 1 and 2, a reduced-pressure system 100for treating a tissue site 102 of a patient 104 with reduced pressure ispresented. The reduced pressure treatment may be used to promote tissuegrowth, help approximate a wound, remove fluids, or other purposes.Unless otherwise indicated, as used throughout this document, “or” doesnot require mutual exclusivity. The tissue site 102 may be, as anon-limiting example, an incision 106. The incision 106 is shown with astitch 108 helping to hold the incision 106 in a closed position. Theincision 106 may be through the patient's 104 epidermis 110, dermis 112,and into the subcutaneous tissue 114. The tissue site 102 may be thebodily tissue of any human, animal, or other organism, including bonetissue, adipose tissue, muscle tissue, dermal tissue, vascular tissue,connective tissue, cartilage, tendons, ligaments, or any other tissue.

The reduced-pressure system 100 includes a distribution manifold 116that is disposed adjacent to the tissue site 102. The distributionmanifold 116 includes a porous member 118 having a plurality of flowchannels for distributing reduced pressure and receiving fluids. Theporous member 118 has a first side 120 and a second, tissue-facing side122. As shown best in FIG. 2, the distribution manifold 116 may alsoinclude a fluid-permeable substrate member 124 having a first side 125and a second, tissue-facing side 127. The second, tissue-facing side 122of the porous member 118 is proximate to the first side 125 of thefluid-permeable substrate member 124. The second, tissue-facing side 127of the fluid-permeable substrate member 124 has a surface area A_(s).

The porous member of the distribution manifold 116 refers to a substanceor structure that is provided to assist in applying reduced pressure to,delivering fluids to, or removing fluids from a tissue site. The porousmember 118 typically includes a plurality of flow channels or pathwaysthat distribute fluids provided to and removed from the tissue site 102around the distribution manifold 116. In one illustrative embodiment,the flow channels or pathways are interconnected to improve distributionof fluids provided or removed from the tissue site 102. The porousmember 118 may be a biocompatible material that may be placed directlyin contact with the tissue site 102 and distributes reduced pressure.Examples of porous members 118 may include, without limitation, devicesthat have structural elements arranged to form flow channels, such as,for example, cellular foam, open-cell foam, porous tissue collections,liquids, gels, and foams that include, or cure to include, flowchannels. The porous member 118 may be made from foam, gauze, feltedmat, or any other material suited to a particular biologicalapplication. In one embodiment, the porous member 118 is a porous foamand includes a plurality of interconnected cells or pores that act asflow channels. The porous foam may be a polyurethane, open-cell,reticulated foam such as GranuFoam® material manufactured by KineticConcepts, Incorporated of San Antonio, Texas. In some situations, theporous member 118 may also be used to distribute fluids such asmedications, antibacterials, growth factors, and various solutions tothe tissue site 102. Other layers may be included in or on the porousmember 118, such as absorptive materials, wicking materials, hydrophobicmaterials, and hydrophilic materials.

In one illustrative embodiment, the porous member 118 may be constructedfrom a bioresorbable material that if used with an open wound does nothave to be removed from a patient's body following use. Suitablebioresorbable materials may include, without limitation, a polymericblend of polylactic acid (PLA) and polyglycolic acid (PGA). Thepolymeric blend may also include without limitation polycarbonates,polyfumarates, and capralactones. The porous member 118 may furtherserve as a scaffold for new cell-growth, or a scaffold material may beused in conjunction with the porous member 118 to promote cell-growth. Ascaffold is a substance or structure used to enhance or promote thegrowth of cells or formation of tissue, such as a three-dimensionalporous structure that provides a template for cell growth. Illustrativeexamples of scaffold materials include calcium phosphate, collagen,PLA/PGA, coral hydroxy apatites, carbonates, or processed allograftmaterials. The porous member 118 may take any shape, e.g., a rectangle,a square, triangle, a circle, or any other shape.

As shown in FIG. 2, the lateral edges 123 of the porous member 118 maybe shaped edges to offload smoothly forces on the porous member 118 tothe tissue site 102 or areas near the tissue site 102. For example, thelateral edges 123 of the porous member 118 may be formed, as anon-limiting example, at a 45 degree angle as shown or a 30 degree angleor another angle that helps off load forces. As explained later inconnection with FIGS. 10 and 11, the porous member 118 may have notchesformed on the first side 120 to enhance flexibility of the porous member118.

The distribution manifold 116 may include the fluid-permeable substratemember 124. The fluid-permeable substrate member 124 is operational toprevent or inhibit irritation of the tissue site 102 by the porousmember 118. The fluid-permeable substrate member 124 may be a wovenmaterial, non-woven material (using such fiber forming polymers aspolyvinyl alcohols, polyvinyl acetates, polyethylenes, polyesters,polyamides, polyacrylics and polyacrylates, cellulosics and theircopolymers, and where non ionizing radiation methods of sterilizationare used, polypropylene), fenestrated drape or film (using suchfiber-forming polymers as just listed), a high density foam (higherdensity than the porous member 118) or any material that inhibitsirritation of the tissue site 102 by the porous member 118 whileallowing fluid transmission. The fluid-permeable substrate member 124may make attachment of a tissue-fixation element 126 (described furtherbelow) easier. The fluid-permeable substrate member 124 may be coupledto the distribution manifold 116 using an adhesive bond, flamelamination or heat lamination, spray adhesive, hot melt, or any otherdevice or technique. The fluid-permeable substrate member 124 may becoupled to the distribution manifold 116 by forming an integral foam orfilm such as by using compressed or felting foams and co-blown foam andfilm.

The fluid-permeable substrate member 124 may contain medicaments, e.g.,antimicrobials, lidocaine, or other substances, to treat the tissue site102. The fluid-permeable substrate member 124 may be a solid substrateor may only partially cover the porous member 118. Coupled includescoupling via a separate object and includes direct coupling. The termcoupled also encompasses two or more components that are continuous withone another by virtue of each of the components being formed from thesame piece of material. Coupling may also include chemical, such as viaa chemical bond, mechanical, thermal, or electrical coupling. Fluidcoupling means that fluid may be in communication between the designatedparts or locations.

The distribution manifold 116 includes the tissue-fixation element 126.As will be explained more further below, the tissue-fixation element 126is operational to tack or at least temporarily attach the distributionmanifold 116 to the tissue site 102 while other aspects of thereduced-pressure system 100 are applied. The tissue-fixation element 126has a first side 128 and a second, tissue-facing side 130. The firstside 128 of the tissue-fixation element 126 may be coupled to thesecond, tissue-facing side 127 of the fluid-permeable substrate member124 or in some embodiments directly to the second, tissue-facing side122 of the porous member 118. The second, tissue-facing side 130 of thetissue-fixation element 126 has a surface area A. The tackiness oftissue-fixation element 126 may be such that the tissue-fixation element126 will separate from the tissue site 102 before the fluid-permeablesubstrate member 124 separates from the porous member 118. In otherwords, the strength of tackiness of the tissue-fixation element 126 tothe tissue site 102 is less than the strength of the bond between thetissue-fixation element 126 and the fluid-permeable substrate member124.

The relationship of the surface area A_(t) of the tissue-fixationelement 126 to the surface area A_(s) of the fluid-permeable substratemember 124 may be 0.05 A_(s)<A_(t)<0.6 A_(s). Other relationshipsbetween the surface areas A_(t), A_(s) are contemplated. Asnon-limiting, illustrative examples, the following relationships may berealized: 0.10 A_(s)<A_(t)<0.8 A_(s), 0.10 A_(s)<A_(t)<0.5 A_(s), 0.15A_(s)<A_(t)<0.4 A_(s), 0.20 A_(s)<A_(t)<0.4 A_(s), or otherrelationships. The relationship of the surface areas is such that for agiven tackiness of a tissue-fixation element 126, the surface area A_(t)provides adequate force to hold the distribution manifold 116 adjacentto the tissue site 102 notwithstanding gravitational forces from thegravitational field 131. In the illustrative embodiments that do notutilize the fluid-permeable substrate member 124, the relationships areanalogous as between the surface area A_(p) of the second, tissue-facingside 122 of the porous member 118 and the area A_(t) of thetissue-fixation element 126, e.g., 0.05 A_(p)<A_(t)<0.7 A_(p).

The tissue-fixation element 126 may take numerous shapes or formnumerous patterns. For example, the tissue-fixation element 126 maycomprise spaced strips or lines coupled to the second, tissue-facingside 127 of the fluid-permeable substrate member 124 (or alternativelythe second, tissue-facing side 122 of the porous member 118) as shown inFIGS. 3 and 4. Other examples of patterns the tissue-fixation element126 may take include, without limitation, islands or circles (uniform orrandom) as shown in FIG. 5, concentric circles as shown in FIG. 6, meshas shown in FIG. 7, concentric squares, triangles, diamonds, or anyother pattern. Typically, the pattern will involves less than 100percent coverage of the second, tissue-facing side 127 of thefluid-permeable substrate member 124 (or alternatively the second,tissue-facing side 122 of the porous member 118), but if atissue-fixation element 126 is used that allows fluid migration throughthe tissue-fixation element 126, 100 percent (100%) coverage may beused. As non-limiting examples, in FIG. 3, A_(t) is approximately 25%(0.25) of As, and in FIG. 4, A_(t) is approximately 50% (0.5) of A_(s).

The tissue-fixation element 126 may be a water-soluble adhesive or anon-water-soluble adhesive. In one illustrative embodiment, thetissue-fixation element 126 is a water-soluble adhesive that dissolvesat least after one hour of contact with liquid and yet remains at least10 minutes in contact with a liquid. In another illustrative embodiment,the tissue-fixation element 126 is an adhesive activated by contact withan aqueous liquid. In another illustrative embodiment, thetissue-fixation element 126 is a water-soluble adhesive that remains forat least ten minutes when in contact with a liquid and substantiallydissolves at least within one hour or within three hours of contact witha liquid. In some embodiments using a water-soluble adhesive, if a userdesires to increase the rate of dissolution of the tissue-fixationelement 126, a saline solution may be injected into the porous member118.

With the non-water soluble version of the tissue-fixation element 126,the extent of the tissue-fixation element 126 on the porous member 118or fluid-permeable substrate member 124 is adequate to allow flow ofreduced pressure through the distribution manifold 116 for treatmentfrom the start and at the same time adequate to tack to keep thedistribution manifold 116 in place even when directly opposed by thegravitation field 131. In some embodiments, the tackiness of thetissue-fixation element 126 may be varied in strength at differentlocations on the porous member 118 or fluid-permeable substrate member124.

In embodiments using a non-soluble tissue-fixation element 126, anon-soluble adhesive may be used. Non-limiting examples of non-solubleadhesives include colloids, hydrogels, silicone, lastomers, acrylics,polyurethanes, and polyvinyl acetates. In embodiments using awater-soluble tissue-fixation element 126, a water-soluble dispersibleadhesive may be used to form the tissue-fixation element 126.Non-limiting examples of soluble or water sensitive dispersibleadhesives that might be used include the following: Polyvinyl alcohol(PVOH), polyvinyl pyrrolidone (PVP), polyethylene oxide (PEO),polypropylene oxide (PPO), modified cellulose (such as carboxymethylcellulose [CMC]) and cellulose ethers, hydroxyl and carboxy modifiedpolymers, such as poly acrylics, poly acrylates, poly amides,polyesters, and polyurethanes and their salts (for example sodium,potassium, and ammonium), polyacrylamides, gums such as guar andxanthan, polyethylene glycols. Also, water solubility may be triggeredthrough a change in pH or by substitution. For example, formation of asodium salt from a carboxyl group to form a sodium carboxylate may bethe trigger. These changes may be brought about using external sources,such as adding a high pH solution to the dressing (wound) where acarboxy functionality (acidic) is neutralized and made water soluble, orthe additive is within the polymer matrix, becoming active and mobile onthe absorption of moisture (from the wound or and external source, e.g.instillation). One commercially available water soluble substance thatmay be sufficient is a “Water Soluble Tape,” which is used in wavesoldering of circuit boards, and is available from 3M of St. Paul, Minn.The tissue-fixation element 126 may be formed with various medicaments,e.g., silver, included to provide additional therapy benefits. Thetissue-fixation element 126 may also be formed from gels or colloidsthat provide additional conditioning of the tissue site 102 or thatmight help reduce irritation near the tissue site 102 being treated.

As shown in FIG. 2, a release liner 129 may be used to cover the second,tissue-facing side 130 of the tissue-fixation element 126. The releaseliner 129 covers the second, tissue-facing side 130 of thetissue-fixation element 126 for storage or before the tissue-fixationelement 126 is applied. The release liner 129 has a first side 135 and asecond, tissue-facing side 137. In a stored state, the first side 135 ofthe release liner 129 is removably coupled to the second, tissue-facingside 130 of the tissue-fixation element 126.

Referring again primarily to FIG. 1, the reduced-pressure system 100further includes a sealing member 132 for disposing over thedistribution manifold 116 and a portion of intact epidermis 110 tocreate a sealed space 133 containing the distribution manifold 116. Thesealing member 132 may be any material that provides a fluid seal. Afluid seal is a seal adequate to maintain reduced pressure at a desiredsite given the particular reduced-pressure source or subsystem involved.The sealing member 132 may, for example, be an impermeable orsemi-permeable, elastomeric material. Elastomeric materials have theproperties of an elastomer. Elastomeric generally refers to a polymericmaterial that has rubber-like properties. More specifically, mostelastomers have ultimate elongations greater than 100% and a significantamount of resilience. The resilience of a material refers to thematerial's ability to recover from an elastic deformation. Examples ofelastomers may include, but are not limited to, natural rubbers,polyisoprene, styrene butadiene rubber, chloroprene rubber,polybutadiene, nitrile rubber, butyl rubber, ethylene propylene rubber,ethylene propylene diene monomer, chlorosulfonated polyethylene,polysulfide rubber, polyurethane (PU), EVA film, co-polyester, andsilicones. Additional, specific examples of sealing member materialsinclude a silicone drape, a 3M Tegaderm® drape, or a polyurethane (PU)drape such as one available from Avery Dennison Corporation of Pasadena,Calif.

The sealing member 132 may have an attachment device 134 on atissue-facing side 136. The attachment device 134 may be used to holdthe sealing member 132 against the patient's epidermis 110 or anotherlayer, such as a gasket or additional sealing member. The attachmentdevice 134 may take numerous forms. For example, the attachment device134 may be a medically acceptable, pressure-sensitive adhesive thatextends about a periphery or all of the sealing member 134. Asadditional examples, the attachment device 134 may be a double-sideddrape tape, paste, hydrocolloid, hydro gel or other sealing devices orelements.

The reduced-pressure system 100 further includes a reduced-pressuresource 138 that may be fluidly coupled to the sealed space 133 and tothe distribution manifold 116. The reduced-pressure source 138 may becoupled by a reduced-pressure delivery conduit 140 to a reduced-pressureinterface 142. The reduced-pressure source 138 may be an external sourceas shown in FIG. 1 and may be fluidly coupled with the reduced-pressuredelivery conduit 140. Alternatively, the reduced-pressure source 138 maybe incorporated into the porous member 118 or disposed adjacent to thedistribution manifold 116. The reduced-pressure source 138 may be anydevice for supplying a reduced pressure, such as a vacuum pump, wallsuction, micro-pump, or other source. While the amount and nature ofreduced pressure applied to a tissue site will typically vary accordingto the application, the reduced pressure will typically be between −5 mmHg (−667 Pa) and −500 mm Hg (−66.7 kPa) and more typically between −75mm Hg (−9.9 kPa) and −300 mm Hg (−39.9 kPa), and more typically stillbetween −100 mm Hg (−13.3 kPa) and −150 mm Hg (−19.9 kPa).

In some embodiments of the reduced-pressure system 100, thereduced-pressure interface 142 provides fluid communication to thesealed space 133. In one illustrative embodiment, the reduced-pressureinterface 142 is a T.R.A.C.® Pad or Sensa T.R.A.C.® Pad available fromKCI of San Antonio, Tex.

Reduced pressure generally refers to a pressure less than the ambientpressure at a tissue site that is being subjected to treatment. In mostcases, this reduced pressure will be less than the atmospheric pressureat which the patient is located. Alternatively, the reduced pressure maybe less than a hydrostatic pressure at the tissue site. Reduced pressuremay initially generate fluid flow in the distribution manifold 116,reduced-pressure delivery conduit 140, and proximate the tissue site102. As the hydrostatic pressure around the tissue site 102 approachesthe desired reduced pressure, the flow may subside, and the reducedpressure may be maintained. Unless otherwise indicated, values ofpressure stated herein are gauge pressures. The reduced pressuredelivered may be constant or varied (patterned or random) and may bedelivered continuously or intermittently. Consistent with the useherein, an increase in reduced pressure or vacuum pressure typicallyrefers to a relative reduction in absolute pressure.

A liquid receptor 144 may be fluidly coupled to (or included as anaspect of) the distribution manifold 116 for receiving fluids from thepatient 104 under the influence of reduced pressure provided by thereduced-pressure source 138. The liquid receptor 144 may be a canister146 as shown in FIG. 1 or may be an absorbent layer associated with thedistribution manifold 116.

Referring primarily to FIGS. 1 and 2, in operation according to oneillustrative embodiment, the distribution manifold 116 is sized for thetissue site 102 by selecting an appropriately sized distributionmanifold 116 or cutting the distribution manifold 116 to size. Ifapplicable, the distribution manifold 116 is prepared for application byremoving the release liner 129. The second, tissue-facing side 130 ofthe tissue-fixation element 126 is disposed adjacent to the tissue site102. The tissue-fixation element 126 adheres, at least temporarily, tothe tissue site 102. The distribution manifold 116 thus remainssubstantially adjacent to the tissue site 102. In this way, the patient104 may have the tissue site 102 parallel to the gravitational field 131and nonetheless the distribution manifold 116 will remain at the desiredlocation on the tissue site 102. The distribution manifold 116 mayremain against the tissue site 102 even when all exterior support hasbeen removed such that the distribution manifold 116 is suspended byonly the tissue-fixation element 126 and perhaps to some extent by thetissue site 102 itself. In other words, the distribution manifold 116may be retained adjacent to the tissue site 102 without any additionaltools or supports other than the tissue-fixation element 126.

The sealing member 132 may then be disposed over the distributionmanifold 116 and a portion of the intact epidermis 110 to create thesealed space 133. The distribution manifold 116 is disposed in thesealed space 133. If not already applied, the reduced-pressure interface142 may be applied to the sealing member 132. The reduced-pressuredelivery conduit 140 may be fluidly coupled between the reduced-pressuresource 138 and the reduced-pressure interface 142. The reduced-pressuresource 138 is activated and reduced pressure is thereby supplied to thesealed space 133 and fluids may flow from the tissue site 102 to theliquid receptor 144. The pattern of the tissue-fixation element 126 mayallow a contracting force to be experienced in 360 degrees at the tissuesite 102 during treatment. The contracting force is developed bycontraction of the distribution manifold 116 or the sealing member 132under the influence of reduced pressure.

In embodiments using a water-soluble tissue-fixation element 126, thetissue-fixation element 126 initially retains the distribution manifold116 adjacent to the tissue site 102 and then with time thetissue-fixation element 126 dissolves. In one illustrative embodiment,the tissue-fixation element 126 remains at least ten (10) minutes incontact with a liquid and dissolves at least within one (1) hour, two(2) hours, or three (3) hours of contact with liquid. Because of thepartial coverage of second, tissue-facing side 122 of the porous member118 or fluid-permeable substrate member 124 by the tissue-fixationelement 126, reduced pressure may immediately flow through thedistribution manifold 116 to the tissue site 102 and may do so with moreavailable flow paths as the tissue-fixation element 126 dissolves. Inother embodiments, using a non-water-soluble tissue-fixation element126, the pattern of the tissue-fixation element 126 remains and allowsadequate flow between portions of the tissue-fixation element 126 or thetissue-fixation element 126 itself may allow fluid flow through thetissue-fixation element 126, i.e., the tissue-fixation element 126 maybe fluid permeable.

Referring now primarily to FIG. 8, a portion of another illustrativeembodiment of a reduced-pressure system 100 is presented. Thereduced-pressure system 100 of FIG. 8 is analogous to thereduced-pressure system 100 of FIG. 1 with two main differences: aplurality of malleable members 152 have been added to the porous member118 and the fluid-permeable substrate member 124 extends beyond thelateral edge 123 of the porous member 118.

The plurality of malleable members 152 plastically deform thedistribution manifold 116 in order to accommodate a curved surface ofthe patient 104, such as a leg, arm, breast, or a complex surface. Theplurality of malleable members 152 may be formed from steel or anyplastically deformable members. While in cross section only one of theplurality of malleable members 152 is shown, it should be understoodthat any number of spaced members may be included. In operation, thedistribution manifold 116 is plastically deformed to the shape of thecurved surface of the patient 104 to be treated. The plurality ofmalleable member 152 retain the shape. The reduced-pressure system 100may then be applied analogously to the deployment previously presented.

Referring now primarily to FIG. 9, a top view of a portion of anotherillustrative embodiment of a reduced-pressure system 100 is presented.The porous member 118 is shown with broken lines on an incision 106,which is also shown with broken lines. In this embodiment, thetissue-fixation element 126 extends beyond the porous member 118 to forman extension portion 154. The extension portion 154 helps off loadforces to the epidermis 110 of the patient 104. In other embodiments,the fluid-permeable substrate member 124 may extend beyond the porousmember 118 to offload forces.

Referring now primarily to FIG. 10, another illustrative embodiment of adistribution manifold 116 is presented. In FIG. 10, the sealing member132 has not yet been applied. The distribution manifold 116 of FIG. 10is analogous to the previous embodiments except that a plurality ofnotches 156 or cuts have been formed on the first side 120 of the porousmember 118. The plurality of notches 156 help the distribution manifold116 to flex or curve with a body part of the patient 104 or withmovement of the patient's body. The plurality of notches 156 may belateral cuts as suggested in FIG. 10, a grid or mesh pattern of cuts asshown in FIG. 11, hexagonal shaped cuts as shown in FIG. 12, or anothershape.

In another illustrative embodiment, the tissue-fixation element 126 maybe a liquid-activated adhesive. In such an embodiment, thetissue-fixation element 126 may be activated by liquids at the tissuesite from the wound, saline, or skin preparation liquids. The userdisposes the liquid-activated adhesive of the tissue-fixation element126 against the tissue site 102 and allows the liquids present toactivate the tackiness of the tissue-fixation element 126.

In another illustrative device, the tissue-fixation element 126 may beincluded as an aspect of the fluid-permeable substrate member 124. Forexample, in one illustrative embodiment, the fluid-permeable substratemember 124 may be a woven material with super absorbent fibers woveninto the material. The super absorbent fibers become tacky whenmoistened. Other fibers or materials may be included in thefluid-permeable substrate member 124 to provide tackiness when moist,such as other water sensitive or crosslinked water soluble polymers(e.g., polyvinyl alcohol, carboxymethyl cellulose, alginates, and othernatural gums such as xanthan and guar).

In another illustrative embodiment, a tissue-fixation element 126 may bestored separately with release liners, e.g., release liner 129, on boththe first side 128 and the second, tissue-facing side 130. In use, therelease liner is removed from the first side 128 and applied to thesecond, tissue-facing side 122 of the porous member 118 or the second,tissue-facing side 127 of the fluid-permeable substrate member 124. Thenthe release liner is removed from the second, tissue-facing side 130 ofthe tissue-fixation element 126, and the tissue-fixation element 126 isbrought into contact with the tissue site 102. Alternatively, therelease liner may first be removed from the second, tissue-facing side130 of the tissue-fixation element 126 and applied to the tissue site102. Then the release liner may be removed from the first side 128 ofthe tissue-fixation element 126 and the porous member 118 orfluid-permeable substrate member 124 applied adjacent to thetissue-fixation element 126. In another illustrative embodiment, thetackiness and strength of the tissue-fixation element 126 may be suchthat the tissue-fixation element 126 supplements the sutures orfunctions as sutures in holding an incision 106 in a closed position.

In another illustrative device, the sealing member 132 may be applied tothe first side 120 of the porous member 118 and the tissue-fixationelement 126 may be coupled to the second, tissue-facing side 127 of thefluid-permeable substrate member or the second, tissue facing side 122of the porous member 118. The release liner 129 may cover the second,tissue-facing side 130 of the tissue-fixation element 126 and thesecond, tissue-facing side 139 of the sealing member 132. In this way,removing the release liner 129 in order to apply the sealing member 132assures that the release liner 148 has also been removed from thetissue-fixation element 126.

With the illustrative embodiments herein, a distribution manifold 116may be applied by a single user without requiring additional tools tohold the porous member 118 in place while the sealing member 132 isapplied. Moreover, the user may have two hands available to apply thesealing member 132. The tackiness of the tissue-fixation element 126 maybe such that the user may reposition the porous member 118 relative tothe tissue site 102 before the sealing member 132 is applied.

In addition, the distribution manifold 116 may be applied with thepatient in a prevailing position, which is a position that the patientwill remain for a majority of time during treatment. This means apatient with a tissue site 102 that is on a vertical surface (parallelto the gravitational field 131) may have the distribution manifold 116applied while remaining in the vertical position. In contrast, if adistribution manifold 116 on such a patient 104 is applied to the tissuesite 102 in the horizontal position (orthogonal to gravitational field131), when the patient again assumes a vertical position, they may findthe distribution manifold 116 pulling and fitting in ways that are notcomfortable to the patient.

Although the present invention and its advantages have been disclosed inthe context of certain illustrative embodiments, it should be understoodthat various changes, substitutions, permutations, and alterations canbe made without departing from the scope of the invention as defined bythe appended claims. It will be appreciated that any feature that isdescribed in connection to any one embodiment may also be applicable toany other embodiment. For example, the malleable members 152 of FIG. 8may be included in the embodiment of FIG. 1.

We claim:
 1. A reduced-pressure system for treating a tissue site,comprising: a porous member comprising a plurality of flow channels fordistributing reduced pressure, the porous member including a first sideand a second side; a liquid receptor associated with the porous memberand configured to receive fluids; a tissue-fixation element comprisingan extension portion extending beyond the porous member; and a sealingmember comprising an attachment device configured to hold the sealingmember against at least the extension portion of the tissue-fixationelement.
 2. The system of claim 1, wherein the porous member comprisesfoam.
 3. The system of claim 1, wherein the liquid receptor comprises anabsorptive layer positioned on the porous member.
 4. The system of claim1, wherein the liquid receptor comprises an absorptive material includedwithin the porous member.
 5. The system of claim 1, wherein thetissue-fixation element partially covers the second side of the porousmember.
 6. The system of claim 1, wherein the tissue-fixation element isconfigured to allow fluid flow between portions of the tissue-fixationelement on the second side of the porous member.
 7. The system of claim1, wherein the tissue-fixation element comprises a spaced pattern ofcircles.
 8. The system of claim 1, wherein the tissue-fixation elementcomprises silicone.
 9. The system of claim 1, wherein a portion of thetissue-fixation element is positioned on the second side of the porousmember.
 10. The system of claim 1, wherein a tackiness strength of thetissue-fixation element relative to the tissue site is configured to beless than a bond strength between the tissue-fixation element and theporous member.
 11. The system of claim 1, wherein the tissue-fixationelement is configured to allow fluid to migrate through thetissue-fixation element.
 12. The system of claim 1, wherein thetissue-fixation element is configured to be positioned adjacent to thetissue site.
 13. The system of claim 1, wherein the attachment deviceextends at least about a periphery of the sealing member.
 14. The systemof claim 1, wherein the attachment device is a pressure-sensitiveadhesive.
 15. The system of claim 1, wherein the porous member furthercomprises a plurality of notches formed on the first side of the porousmember and configured to provide flexibility.
 16. The system of claim 1,further comprising a reduced-pressure source configured to providereduced pressure to the porous member.
 17. A system for treating atissue site with reduced pressure, the system comprising: a porousmember comprising a plurality of flow channels, the porous memberincluding a first side and a second side; an absorptive layer positionedon the porous member and configured to receive fluids from the porousmember; a tissue-fixation element positioned proximate to the secondside of the porous member, wherein the tissue-fixation element isconfigured to allow fluid flow between portions of the tissue-fixationelement; and a sealing member configured to be applied to the first sideof the porous member and to create a sealed space.
 18. The system ofclaim 17, wherein the tissue-fixation element comprises a spaced patternconfigured to allow fluid flow between portions of the tissue-fixationelement.
 19. The system of claim 17, wherein the tissue-fixation elementcomprises silicone.
 20. The system of claim 17, wherein thetissue-fixation element is configured to be positioned adjacent to thetissue site.
 21. The system of claim 17, wherein a tackiness strength ofthe tissue-fixation element relative to the tissue site is configured tobe less than a bond strength between the tissue-fixation element and theporous member.
 22. The system of claim 17, wherein the sealing membercomprises an attachment device on a tissue-facing side of the sealingmember, wherein the tissue-fixation element extends beyond the porousmember to form an extension portion, and wherein the attachment deviceis configured to hold the sealing member against at least the extensionportion of the tissue-fixation element.
 23. The system of claim 22,wherein the attachment device extends at least about a periphery of thesealing member.
 24. The system of claim 22, wherein the attachmentdevice is a pressure-sensitive adhesive.
 25. A system for treating atissue site with reduced pressure, the system comprising: a porousmember comprising a plurality of flow channels and including a firstside and a second side; an absorptive layer configured to receive fluidsfrom the tissue site; a tissue-fixation element configured to extendbeyond the porous member to form an extension portion, wherein thetissue-fixation element is configured to allow fluid flow between thetissue site and at least the absorptive layer and the porous member; anda sealing member configured to be applied to the first side of theporous member and to create a sealed space, wherein the sealing membercomprises an attachment device on a tissue-facing side of the sealingmember, and wherein the attachment device is configured to hold thesealing member against at least the extension portion of thetissue-fixation element.
 26. The system of claim 25, wherein theattachment device extends at least about a periphery of the sealingmember.
 27. The system of claim 25, wherein the attachment device is apressure-sensitive adhesive.
 28. The system of claim 25, wherein thetissue-fixation element comprises a spaced pattern configured to allowfluid flow between portions of the tissue-fixation element.
 29. Thesystem of claim 25, wherein the tissue-fixation element comprisessilicone.
 30. The system of claim 25, wherein the tissue-fixationelement is configured to be positioned adjacent to the tissue site. 31.The system of claim 25, wherein the absorptive layer is positioned onthe porous member.
 32. A dressing for treating a tissue site withreduced pressure, the dressing comprising: a distribution manifoldcomprising: a fluid-permeable substrate, an absorbent layer, and atissue-fixation element configured to allow fluid flow through thedistribution manifold; and a sealing member configured to be disposedover the distribution manifold.
 33. The dressing of claim 32, whereinthe fluid-permeable substrate comprises a woven material.
 34. Thedressing of claim 32, wherein the tissue-fixation element comprises anadhesive.
 35. The dressing of claim 32, wherein the tissue-fixationelement comprises an adhesive that is not soluble in water.
 36. Thedressing of claim 32, wherein the tissue-fixation element comprisessilicone.
 37. The dressing of claim 32, wherein the tissue-fixationelement comprises silicone gel.
 38. The dressing of claim 32, whereinthe tissue fixation element comprises silicone gel having a pattern thatcovers at least 10 percent and less than 100 percent of thefluid-permeable substrate.
 39. The dressing of claim 32, wherein thesealing member comprises an attachment device configured to hold thesealing member against at least a portion of the tissue-fixationelement.
 40. The dressing of claim 32, wherein: the fluid-permeablesubstrate comprises a woven material; the tissue fixation elementcomprises silicone gel having a pattern that covers at least 10 percentand less than 100 percent of the fluid-permeable substrate; and thesealing member comprises an attachment device configured to hold thesealing member against at least a portion of the tissue-fixationelement.